Management of Abnormal Pap Smears During Pregnancy
Pregnant women should have Pap smears as part of routine prenatal care, and abnormal results require colposcopic evaluation with selective biopsy only when high-grade lesions or cancer are suspected—pregnancy itself can cause reactive cellular changes that may lead to false-positive results. 1
Understanding False Positives in Pregnancy
Pregnancy creates physiological changes that can lead to false-positive Pap smear interpretations:
- Hormonal influences during pregnancy alter cervical cytology, causing reactive cellular changes that may be misinterpreted as dysplasia 2, 3
- Severe inflammation with reactive squamous cellular changes is common during pregnancy and should prompt repeat testing rather than immediate intervention 1
- Previous treatment for cervical dysplasia or pregnancy status are known risk factors for false-positive malignant cytology 3
- Post-partum Pap smears may reveal different results than those obtained during pregnancy, with studies showing discordant results in patients who were negative during pregnancy 2
Initial Management Algorithm
For Severe Inflammation with Reactive Changes:
- Repeat Pap smear within 3 months after treating any underlying infection 1
- Treat cervicitis or infection before obtaining the repeat specimen to optimize accuracy 1
For ASCUS or Low-Grade SIL:
- Colposcopy is recommended, though some experts consider repeat Pap smear an acceptable alternative in select situations 1
- The threshold for biopsy during pregnancy is often modified, but this may be harmful—do not avoid necessary biopsies 4
For High-Grade SIL or Malignancy:
- Immediate referral for colposcopy and directed biopsy is mandatory 1
- Do not defer biopsy based solely on pregnancy status when colposcopy suggests CIN 2 or greater 4
Critical Pitfalls to Avoid
The most dangerous error is failing to perform colposcopically-directed biopsy when indicated during pregnancy:
- A study found that 83.6% of pregnant patients with colposcopic findings suggesting CIN 2 or greater did not undergo biopsy, and four patients were subsequently diagnosed with invasive cervical carcinoma within 12 months post-delivery 4
- Pregnancy is not a contraindication to cervical biopsy when high-grade lesions are suspected 4
- Patient compliance with follow-up is poor—only 26% of patients scheduled for repeat colposcopy during pregnancy complied, and only 42% returned post-partum 4
Technical Considerations
Specimen Collection:
- A cytobrush may be used during pregnancy, but care must be taken not to disrupt the mucous plug 1
- Liquid-based cytology is preferred as it reduces inadequate specimens and false-negative results 1
- The cytobrush may cause bleeding, which is more prominent with concurrent STIs—warn patients about possible spotting 1
Timing Considerations:
- Postpone Pap smear if the patient is menstruating 1, 5
- Do not delay testing for mucopurulent discharge—carefully remove discharge with saline-soaked swab before obtaining specimen 5
Follow-Up Strategy
Given poor compliance rates, aggressive follow-up protocols are essential:
- Document all results and provide printed information to patients about their screening 5
- Schedule post-partum follow-up at the one-month visit to catch lesions that may have been obscured by pregnancy-related changes 2
- Develop protocols to identify and follow up with patients who miss appointments 5
- For patients with abnormal results during pregnancy who decline or defer biopsy, mandatory post-partum colposcopy within 6-8 weeks is critical 4